Masonry and Bricks Flashcards
What is masonry?
Blocks of brick held together with mortar
What are the advantages of using masonry?
-Usually locally available stones or clay
-Tends to give high thermal mass
-Usually durable (>500 yrs)
-Usually high fire resistance
What are the disadvantages of using masonry?
-Requires manual labour, hard to mechanise
-Difficult to make very tall structures
-Heavy, needs thick and strong foundation
-Tensile/flexural strength is very limited
-Compressive strength of bricks can also be a limitation
-Unreinforced masonry has low resistance to shearing forces in earthquakes
What material is brickwork?
Usually made from baked clay, iron clay gives a red colour
What is the compressive strength of brickwork?
Can be up to 100 MPa but usually around 20-40 MPa
What is the composition of mortar?
Cement + sand + water
Historically lime was used instead of cement, and is still sometimes used today
What is the strength of mortar under load?
Usually the weakest point under shear load
What is the standard thickness of mortar?
5-10 mm
What are concrete masonry units (CMU) made out of?
Fly ash cement, usually precast with fairly fine aggregates
What does CMU provide a structure?
Light weight and thermal insulation
What is the average compressive strength of CMU?
~20 MPa
What are the structural uses for the materials used to make brick?
-Sand is used for dimensional stability
-Water is needed for effective moulding
-Organic matter or lime accelerates firing
What is the water content of soft mud bricks?
25-30% water - meaning they have more variability
What is the water content of dry press bricks?
~8%, more expensive but give a better product
What is the water content of extruded bricks?
~12%, they are cut by wires from a column of clay, making them very cheap
